RepRaps are 3D printers designed to be able to print many of its own parts (so if you have 1 it is easy to make 2, then 4, then 8…). This also makes the pretty cheap (as little as $600), however at these prices they usually come in kit form.

But, RepRap is also fully OpenSource. This means you are able to get all the construction specs, parts lists, 3d part designs and so forth and source the parts yourself (which can bring the cost down even further). It also means that if you want you can make and sell them yourself, and even modify the design. Many of the cheap 3D printers that are coming onto the market now are based on the RepRaps.

In 3D printing there are several steps to go from your idea to a finished product:
1) Get the digital design. This is usually through a CAD (computer aided design) program like AutoCad, but it can be from any digital source

2) Convert to a 3D printable file. Sometimes this is called “Slice and Dice” as the software used to do this slices the original file into layers so the 3D printer will be able to print each layer one at a time.

3) Convert to printer instructions: This takes the sliced model and works out the code instructions that will tell the printer how to move to print each layer. This is some times called G-Code compiler as the most common instruction set used for this is called G-Code.

4) Print the model. This is where you take the set of instruction (the G-Code) and run it on the 3D printer. The printer then does its stuff and prints out the model.

5) Finishing. This is where you will have to clean up the model (cut off small bits that weren’t meant to be there – a bit like cutting out a plastic model from a sprue) and may be smoothing out any rough areas. Also if the model is meant to be painted, this is where you would paint it.

One thing to note are that the G-Code is usually specific to the particular hardware of the 3D printer, so you will likely have to get the software specific to the 3D printer you have (with Reprap, this is opensource too).

It might sound like a complex process, but it is fairly straight forward. You don’t really have to make many choices in it (you might have to adjust the scale of the model depending where you get the model).

When shopping for a 3D printer, many places will give out free, or cheap samples from their printers so you can see the quality that their printer does.